PRISM :: Browsing by Author "Russell, Anthony P."

Browsing by Author "Russell, Anthony P."

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Open Access
Comparative morphology of the neognath furcula and breast shoulder apparatus: relationships to flight style, diet, and phylogeny
(2009) Knoll, Hollie Mei; Russell, Anthony P.
Open Access
Cranial anatomy and variation of Richardson's ground squirrel (Spermophilus richardsonii)
(1994) Pereschitz, Richard M.; Russell, Anthony P.
Open Access
Distribution characteristics of the eggs, tadpoles, and metamorphs of the northern leopard frog (rana pipiens) and their relation to conservation strategies
(2008) Fraser, Lynne Davidson; Moehrenschlager, Axel; Russell, Anthony P.
Anuran population persistence often hinges on successful metamorph dispersal, but information on this life-stage and its movement characteristics is scarce. Two years of monitoring the emigration patterns of metamorph Northern Leopard Frogs (Rana pipiens), a "Threatened" species in Alberta, revealed that they orient non-randomly upon emigration from their breeding pond. Emigration direction was similar between years and the short-term capture and handling of metamorphs does not appear to disrupt their natural emigration behaviour. Metamorph emigration patterns were not related to the non-random distributions of earlier life-stages ( egg clusters and tadpoles), suggesting that metamorph R. pipiens orient on land using cues other than those detected during their larval period. Natural metamorph dispersal was compared to that of a reintroduced population and results suggest that reintroduced animals do not exhibit natural behaviour. My findings provide insight into the behaviour of metamorph anurans and have implications for R. pipiens conservation in Alberta.
Open Access
Early cretaceous plesiosaurs (sauropterygia: plesiosauria) from northern Alberta: paleoenvironmental and systematic implications
(2006) Druckenmiller, Patrick Scott; Russell, Anthony P.
Open Access
Early to middle triassic ichtyopterygians from the Sulphur Mountain formation of east-central British Columbia, Canada: phylogenetic and evolutionary implications
(2011) Cuthbertson, Robin Scott Renwick; Anderson, Jason; Russell, Anthony P.
Open Access
Evolutionary morphology of the theropod scapulocoracoid
(2003) Jasinoski, Sandra Christine; Russell, Anthony P.
The theropod scapulocoracoid is an integral component of the avian flight apparatus, and its evolution is investigated using a combination of systematically based comparative anatomical and morphometric analyses. The morphological trends revealed via comparisons of theropod taxa are subsequently compared to the results of thin-plate spline analysis, allowing for a more objective assessment of shape changes observed in the scapulocoracoid. Thin-plate splines also permit graphical reconstruction of hypothetical ancestral forms situated at the internal nodes within a cladogram. The transformations inferred for the hypothetical ancestors, which represent more accurately the true line of descent, are compared to the transitions between the terminal taxa. In order to evaluate changes in the size and performance of the shoulder girdle musculature during this transition, theropod shoulder girdle musculature is reconstructed, based upon phylogenetic and functional inferences. Identification and comparison of osteological correlates of theropod shoulder musculature across theropod groups, and areas of shape change in the scapulocoracoid as revealed by anatomical comparisons, allow muscular changes to be mapped onto structural intermediates leading up to birds.
Open Access
Food level effects on metamorphic timing in the long-toed salamander, ambystoma macrodactylum krausei
(1997) Watson, Sheri; Russell, Anthony P.
Embargo
Form, function and biological role in the locomotory apparatus of the genus Odocoileus in Alberta (Mammalia: Artiodactyla)
(1977) Eslinger, Dale H.; Russell, Anthony P.
Open Access
Functional morphology of the tyrannosaurid arctometatarsus
(2000) Snively, Eric; Russell, Anthony P.
Open Access
In ovo development of the head skeleton of the leopard gecko (eublepharis macularius)
(2009) Wise, Patrick Arthur David; Russell, Anthony P.
Open Access
Laryngeal morphology of Afro-Madagascan Gekkonine lizards (Gekkonidae: reptilia)
(1995) Rittenhouse, David Richard; Russell, Anthony P.
Open Access
Locomotor morphology of anolis: Comparataive investigations of the design and function of the subdigital adhesive system
(1999) McGregor, Lisa; Russell, Anthony P.
Open Access
Locomotor morphometry of the Pachydactylus radiation of lizards (Gekkota: Gekkonidae): a phylogenetically and ecologically informed analysis
(National Research Council Canada, 2005) Johnson, Megan K.; Russell, Anthony P.; Bauer, Aaron M.
Open Access
Marine vertebrates of the Pembina member of the Pierre Shale (Campanian, upper cretaceous) of Manitoba and their significance to the biogeography of the Western Interior Seaway
(1988) Nicholls, Elizabeth L.; Russell, Anthony P.
The Pembina Member of the Pierre Shale is a black, carbonaceous shale interbedded with seams of bentonite. Lateral continuity of bentonite beds demonstrates a correlation with the Sharon Springs Member of the Pierre Shale and the Baculites obtusus ammonite zone of late Early Campanian age. Lithologic and taphonomic studies suggest that the Pembina was deposited in quiet water, below wave base and that the sediment/water interface was probably anoxic. A large assemblage of marine vertebrate fossils has been collected from the Pembina. These have been salvaged from bentonite mines along the Manitoba Escarpment and are housed in the Morden and District Museum. High numerical abundance and disarticulation of specimens suggest that the Pembina vertebrate assemblage represents an attritional fauna, accumulated over long periods of slow sedimentation rates. No stratigraphic or geographic distributional patterns are evident within the assemblage, and it is treated as a single faunal aggregate. The Pembina vertebrate fauna is described and compared with other Early Campanian marine vertebrate faunas from the Western Interior Seaway. Mosasaurs and birds account for more than half the Pembina fauna, with Platecarpus and Hesperornis being the dominant genera. Diversity within the mosasaur component of the fauna is low, with 83% of the generically identified specimens being Platecarpus. The first North American record of Hainosaurus is reported in the Pembina, and a new species, Hainosaurus pembinensis, is represented. Plesiosaurs (primarily Trinacromerum) are common in the Pembina, and turtles and sharks are rare components of the fauna. Biogeographical hypotheses concerning the distribution of marine vertebrates in the Late Cretaceous Western Interior Seaway are tested by comparing Early Campanian vertebrate faunas spanning the seaway. The following five faunas are considered - the Anderson River, the Pembina, the Sharon Springs, the Niobrara and the Mooreville. The distributional patterns that emerge from these comparisons do not appear to be the result of temporal factors, as identical patterns are observed in a direct comparison of the contemporaneous Pembina and Sharon Springs faunas. These comparisons do not support the hypothesis that local environmental conditions (other than latitude) were of critical importance in determining tetrapod distributions throughout the seaway. The comparisons do support the hypothesis of separate northern and southern biotic subprovinces within the Western Interior Seaway, each with its own distinctive fauna. Latitudinal diversity gradients within marine tetrapod faunas are demonstrated both within the Western Interior Seaway as a whole, and within each biotic subprovince.
Open Access
Morphometry of the limb skeleton of Anolis garmani: practical and theoretical implications
(1997) Myers, Mindy Francine; Russell, Anthony P.
Open Access
Neck musculoskeletal function in the tyrannosauridae (theropoda, coelurosauria): implications for feeding dynamics
(2006) Snively, Eric; Russell, Anthony P.
Open Access
A new centrosaurine ceratopsid from the Oldman Formation of Alberta and its implications for centrosaurine taxonomy and systematics
(National Research Council Canada, 2005) Ryan, Michael J.; Russell, Anthony P.
Open Access
Palaeoecology of vertebrate assemblages from the Upper Cretaceous Judith River group (campanian) of southeastern Alberta, Canada
(1997) Peng, Jianghua; Russell, Anthony P.
Open Access
Patterns of recolonization by tropical anurans following forest habitat alteration
(2010) Weerawardhena, Senarathge Ranjith; Russell, Anthony P.
Open Access
Phylogenetic implications of the morphology and development of the braincase of caecilian amphibians (gymnophiona)
(2011) Maddin, Hillary C.; Russell, Anthony P.; Anderson, Jason
Caecilians, one of the three living groups that comprise Lissamphibia (frogs, salamanders, and caecilians ), are considered the least well understood for many aspects of their biology. The current study set out to develop a framework, within which aspects such as morphology and evolution could be explored, by attempting to resolve the poorly understood phylogeny of caecilians by examining the morphology of the braincase and stapes. The braincases and stapedes of twenty-seven species of caecilian were examined using micro-computed tomography and histologically-prepared specimens. The braincases were first examined for their potential to yield phylogenetic information by deciphering variation in the antotic region. Deriving from assessments of homology based on transmitted structures, eight different patterns of antotic foramina are identified and the distribution of these patterns is congruent with hypotheses of relationships based on molecular data. It is demonstrated that heterochrony was likely a driver of morphological variation; however, causes of such modifications failed to be correlated with the patterns observed. Description of the entire braincase and stapes permitted the identification of thirty-two new morphological characters. These characters are shown to be sufficient for resolving genus-level relationships in the context of previously developed matrices, in a way that is congruent with hypotheses based on molecular data. A combined phylogenetic analysis of morphological and molecular data provides a test of congruence between morphological characters in a total evidence context, permitting ancestral character state reconstructions to be conducted and the plesiomorphic condition of the braincase and stapes of Gymnophiona to be inferred. The ability for the braincase to reveal phylogenetic information in the broader context of lissamphibian phylogeny was explored by considering the auditory apparatus. New observations, combined with those made previously, are used to infer the presence of the lissamphibian-type ear in caecilians, suggesting the secondary loss of the tympanic and opercularis hearing pathways in caecilians. The evolution of the lissamphibian-type ear is most parsimoniously explained under the rnonophyletic ternnospondyl hypothesis of lissamphibian phylogeny. The data presented here, and the new phylogenetic framework incorporating morphology, provide a means to further explore evolution in a group with diverse factors influencing the evolution of morphology.